BACKGROUND AND OBJECTIVES: Colonization of microorganisms on pollutants is the first indication of the potential ability of microbes to utilize plastic pollutants as a carbon source by sequential biodegradation into usable form for sustenance. The Philippines is considered the third highest country contributing to global mismanaged plastic waste. To locally manage and find a natural and innovative solution to this worldwide concern, this study aimed to evaluate the capacity of Xylaria sp. SDM (sterile dark mycelia) wild type, which was previously reported to colonize polyethylene plastic and mutant strains to colonize polystyrene, a plastic pollutant widely produced in the world. Assessment of the ability of local Xylaria sp. strains to grow, penetrate, and damage the surface and inner structures of polystyrene was investigated using scanning electron microscopy (SEM).

METHODOLOGY: Xylaria sp. strains were cultured in a pH 5.0 mineral medium with 0.5% glucose as carbon source and polystyrene as a co-carbon source, and stored at 25?C for 50 days. At the end of the incubation period, due to irremovable fungal strains on the surface of the polystyrene strips, samples of polystyrene from each strain were subjected to SEM.

RESULTS: On the 20th day of incubation, the presence of mucilaginous sheaths and fungal growth was observed on the surface of treated polystyrene strips. At the end of the 50-day incubation period, scanning electron microscopy (SEM) confirmed fungal growth and colonization, through the presence of mycelial mats and hyphae, of the wild type and mutant strains on the surface and inner structures of polystyrene except the control. Moreover, physical surface damage in the form of holes, cracks, and crevices on polystyrene demonstrated the active burrowing action of Xylaria sp. strains further supporting the potential of this fungus to damage polystyrene plastic.

CONCLUSION: Whereas fungal growth on a polymer surface is necessary but not sufficient to conclude the process of carbon assimilation as the final biodegradation step, the initial colonization of Xylaria sp. strains on polystyrene supports its ability to establish itself and physically damage the pollutant. Hence, this study extended the existing knowledge on the colonizing ability of Xylaria sp. on plastic making it a potential candidate organism to biodegrade plastic waste, which is one of the topmost environmental waste hazards in the world today.

Polystyrenes ; Plastics ; Microscopy, Electron, Scanning

BACKGROUND

Ports are susceptible to the arrival of non-indigenous species (NIS) which can subsequently become invasive through maritime traffic. In the Philippines, few studies have been conducted about macrofouling communities in marine vessel-frequented areas. Batangas Port is an international port serving the provinces of Cavite, Laguna, Batangas, Rizal, and Quezon, and docks vessels from areas around the globe. Baseline information of fouling communities in this area is essential as this can allow detection of NIS and alert the community about their presence. It can serve as basis for crafting of guidelines and mitigation measures for possible scenarios regarding the NIS' invasive potential.

METHODOLOGY

Three sampling sites in close proximity to Batangas Port in Brgy. Sta. Clara, Batangas City were studied using biofouling collectors. Fouler collector design was adapted from the North Pacific Marine Sciences Organization (PICES) design. Collectors were deployed in an unused pier, aquaculture pond and mangrove area from November 2014 to January 2015. Retrieved biofoulers were identified using taxonomic keys, and diversity indices were computed.

RESULTS AND DISCUSSION

A total of 1044 individuals were collected in the plates submerged at the sampling sites. These organisms belonged to six phyla and at least nine classes. The community included bivalves, gastropods, polychaetes, and tunicates. A nonindigenous polychaete, Eumida sanguinea, was detected in the retrieval. Values of biodiversity indices indicate low biodiversity, and species evenness values are low as well.

CONCLUSION

The study generated a baseline listing of organisms in the port area and showed a roster of indigenous invertebrates. However, a NIS has been detected. The list is essential as it can be used to alert communities surrounding the port about the presence of NIS so that ecological, economic, and health impacts can be minimized, and monitoring be done regularly.

Animals ; Biofouling ; Invasive Species ; Introduced Species